Counterbalance for oil pumping apparatus



COUNTERBALANGE FOR OIL PUMPING APPARATUS Original Filed Nov. 16, 1936INVENTOR- hheef /Z/'Z4 F/ 40 M r ATTORNEY Patented Apr. 4, .1939

UNITED STATES COUNTERBALANCE FOR OIL PUlVIPING APPARATUS Warren M.Mansfield, Glendale, Calif., assignor to Emsco Derrick & EquipmentCompany, Los Angeles, Calif., a corporation of California ApplicationNovember 16, 1936, Serial No. 111,010

Renewed November 21, 1938 8 Claims.

My invention relates to pumping apparatus commonly employed for pumpingoil from oil wells, and it particularly relates to a counterbalancepumping apparatus and also a unique counterbalance having numerousfeatures and. adva tages over the prior art.

In order that the objects, features, and advantages of my invention maybe better understood I will briefly refer to the oil pumping art inwhich my invention finds extensive use. The pump proper is placed in theWell below the oil level and the pump plmiger thereof is connected bymeans of a string of sucker rods to an operating means at the surface ofthe ground: The operating means includes an operating crank driven bysuitable drive means; and interconnecting means connected between theoperating crank and the string of sucker rods. A very common type ofinterconnecting means has a walking beam connected to the sucker rodsand a pitman connected to the walking beam and the operating crank. Toobtain optimum operating conditions counterbalances are employed tocounterbalance the weight of the string of sucker rods and pump plunger,and approximately one-half the weight of the column of oil supported bythe plunger.

It is an object of my invention to provide pumping apparatus in whichthere is a counterbalance mounted on the operating crank and which isadjustable into various positions to obtain the de- 30 siredcounterbalancing effect.

It is an object of my invention to provide a counterbalance which whenselected for a particular well is of approximately the desired weightand in which the counterbalance may thereafter be adjusted as requiredin order to obtain optimum operating conditions.

It is the usual practice to place the counterbalance so that its centerof mass is on the radial axis of the operating crank. It is found,however, that if the center of mass of the counterbalance is movedforwardly or rearwardly with respect to the radial axis of the crank,that operating conditions may sometimes be improved. It is one of theobjects of my invention to provide a counter- 45 balance in which thecenter of mass thereof may be on the radial axis of the crank or may bemoved forwardly or rearwardly of this axis by a simple adjustment of thecounterbalance.

The rig of the well is used for operations other 50 than pumping, andwhen so used a counterbalance is an interference to the operation of theapparatus and. must, therefore, be eliminated either by detaching itfrom the apparatus or moving it into a concentric or neutral position.It is an object of my invention to provide a counterbalance which may beemployed as a counterbalance during pumping operations and which isadjustable so that it may be positioned with its center of masssubstantially concentric to the center of ro- 5 tation of the operatingcrank on which it is mounted, and in which position acts as a flywheel.7

A further object of my invention is to provide a counterbalance whichincludes two counter- 10 weights positioned on opposite sides of theoperating crank and pivotally connected thereto, and in which thecounterweights are independently adjustable into any position betweenextended, or retracted or neutral position.

It is a further object of my invention to provide a counterbalance ofthe character pointed out in the preceding paragraph which includesseparate adjusting means for each of the counterweights which is in theform of rods, one of which is pivoted to one of the counterweights, theother of which is pivoted to the otherof the counterweights, and inwhich both of the rods are adjustably connected to the operating crank.

A still further object of my invention is to provide a counterbalance inwhich a counterweight thereof is provided with a sideWardly-facingpocket in which extra weights may be secured in order to increase thecounterbalancing effect as desired.

I believe my invention which incorporates the objects and advantagespointed out heretofore to be broadly new and that various modificationsand alterations may be made in the construction without departing fromthe spirit and scope of my invention. For the purpose of teaching thoseskilled in the art as to how my invention may be practiced I haveselected for illustration a preferred form of my invention. It should beunderstood, however, that I do not wish to be limited to'the precisedetails which are disclosed herein. In the accompanying drawing andfollowing description various additional objects, features, andadvantages of my invention will be pointed out.

Referring to the drawing:

Fig. 1 is a diagrammatic View illustrating the utility of my invention.

Fig. 2 is an enlarged elevational view showing the operating crank andcounterbalance of my invention, the counterbalance being in extendedcounterbalancing position.

Fig. 3 is an elevational view taken as indicated by the arrow 3 of Fig.2. 55

Fig. 4 is a fragmentary sectional view taken on the line 4-4 of Fig. 2.

Fig. 5 is a fragmentary sectional view taken on the line 5-5 of Fig. 4.

Fig. 6 is a fragmentary sectional view taken on the line 66 of Fig. 3.

Fig. '7 is a view resembling Fig. 2 but showing the counterbalance inneutral or concentric position.

Referring to the drawing in detail, and particularly Fig. 1, the numeralrepresents the usual type of walking beam which is pivotally supportedon the upper end of a Samson post I2. The right end of the walking beami i is positioned over the well and has secured to it the polish rod ofa string of sucker rods M. This string of sucker rods l4extendsdownwardly into the well through the pump tubing l5 where it isconnected to a plunger of the oil pump (not shown).

Supported in suitable bearings on jack posts I6 is a rotatable driveshaft ll on which is mounted a band wheel l8 driven from a suitabledriving means l9 which'may be a steam engine, gasoline engine, orelectric motor. Mounted on the end of the shaft I1 is an operating crank2|] having a crank pin 22, by means of which it is connected to thelower end of a pitman 23. The upper end of the pitman 23 is connected tothe left end of the walking beam II. An operation of the drive means l9rotates the band wheel l8 and the shaft I? which in turn swings thecrank pin 22 through a circular path. This operates the pitman '23 whichreciprocates the walking beam H and thus reoiprocates the string ofsucker rods Hi. The pump plunger is thus raised and lowered and pumpsoil to the surface of the ground.

As shown in Figs. 1, 2, and 7, a counterbalance 25 of my invention ismounted on the crank 2|.

This crank 2| is secured by a suitable means including a key 26 to theshaft I! so that it is rigidly secured thereon in a radial plane A--Aand so that it rotates on an axis of rotation B. Positioned on oppositesides of the crank 2| are counterweights 28 which are sector shaped, asshown, each including side. faces and an outer curved face. Formed inthe inner corners of each counterweight 2B is a pocket 29, and extendinginto each pocket 29 is a lug or ear 30 which projects outwardly from theside of the crank 2|. Supported by each counterweight 28 is a pivotshaft 3| which extends through the adjacent ear or lug 30 and thuspivotally supports each of the counterweights on opposite sides of thecrank 2|. Each counterweight 28 is swingable in the plane of rotation ofthe crank 2|. The side faces 32 of the counterweights 28 which restadjacent the operating crank 2| when the counterweights are in extendedposition are recessed at 33 so that the counterweights may fit aroundthe extending end of the crank 2|.

Formed in the side faces 3d of each counterweight 28 opposite the walls32 is a pocket 36 through which a pivot pin 31 extends. Placed in eachpocket and rotatable on the pivot pin 31 is a bearing 38. Extending fromeach bearing 38 is a threaded rod 39, each of which extends through alug or projection 46 formed on the hub of the operating crank 2i. Asshown best in Fig. 6, each projection 40 has an opening 4| formed in itwhich is hour-glass shape so that the rod 39 which extends through it isenabled to swing in a plane parallel to the plane of rotation of thecrank 2|. Furthermore, the outer face of each lug 40 is madecylindrical, as indicated at 42, on an axis which extends parallel tothe axis of rotation B. Positioned for engagement with each lug m atopposite ends of the opening 4| is a bearing block 43 having asemicylindrical surface adapted to engage the cylindrical surface 32.Threaded on each rod 39 on opposite sides of each of the blocks 43 arelooking nuts M whereby each rod 39 may be locked in any desired positionwith respect to the lug so, and since each lug fill is mounted on thecrank 2| each rod 39 may thus be locked. with respect to the crank 2|.It will be noted that the upper ends of the rods 39 cross the axis A-A,and that, therefore, these rods must be olfset as shown in Fig. 3, andthat the lugs 10 must also be offset.

The rods 39 and associated parts constitute a means whereby thecounterweight 28 may be moved into any position between extended andretracted position and may furthermore be supported in any of thepositions into which the counterweights may be moved. It will be seenthat the pivots 3i and 37 and the point of the attachment of the upperend of the associated rod 39 form a triangular truss, and that,therefore, each counterweight may be securely retained in the positioninto which it is adjusted. When it is desired to move either or both ofthe counterweights 28 into a different position, such, for example, fromthe position shown in Fig. 2 into the position shown in Fig. 7, thelower nut on each rod is advanced downwardly on each shaft 39 andthereafter the upper nut is advanced downwardly,

thus pulling each rod 39 through the opening M in the associated lug 4%.This causes each counterweight 28 to swing on the pivot 3| and move froma position shown in full lines in Fig. 2 into a position shown in fulllines in Fig. 7.. It will be seen that when this movement occurs thepivot 31 is raised relative to the lug it, and therefore the rod 39 isswung into a less angular position with respect to horizontal, asindicated in full lines in Fig. '7, and by dotted lines it: in Fig. 6.In view of the offsetting of the rods and lugs the rods are able tocross a common plane without interference. The outer corner of eachcounterweight is provided with a slot is through which one of the rods3t extends when the counterweights are in retracted position.

In order that the weight of each counterweight 28 may be increased ordecreased in order to suit the requirements for difierent depths ofwells, each weight is provided with a pocket M formed from the side wall58, thus producing a sidewardly-facing pocket fill defined by a bottomwell t9, an outer wall 55], and side and inner walls 5|. Adapted to beplaced in the pockets of either or both counterweights 28 are extraweights 52 which may be cored out, if desired, as indicated by dottedlines 53, to control their weight. These extra weights 52 are secured inplace by suitable securing bolts 5& which extend through semicylindricalopenings 55 formed in the extra weights 52 and in the outer wall til.The securing means 5% only prevents the weights from falling sidewardlyfrom place, and the outer wall 56 of each pocket ll takes the force setup due to the rotation of the counterweight, and thus produces a firmand mechanically safe connection between these parts.

During the pumping operation the counterbalance is supported incounterbalancing position. If a maximum counterbalancing effect isdesired,

the counterweights 28 are supported in their 75 outermost position, asillustrated in Fig. 2. If less counterbalancing effect is desired, bothof the weights may be swung upwardly with respect to Fig. 2 in order tobring the center of mass of the counterbalance closer to the axis ofrotation B. When the counterweights are held in identical positions,such as shown in Fig. 2, the center of mass of the counterbalance is onthe radial plane AA, If it is desired to shift the center of mass eitherahead or in back of the axis AA, this is done by moving either of thecounterweights 28 relative to the other, such, for example, as indicatedby dotted lines 58 of Fig. 2.

When the rig is to be employed for purposes other than pumping thepitman 23 is disconnected from the crank 2i and the counterweights 28are retracted into the position shown in Fig. 7 which may be designatedas a neutral or flywheel position. When in this position the center ofmass of the counterbalance is substantially concentric to the axis ofrotation B.

From the foregoing it is believed that the important features andadvantages of my invention will be apparent. It will be seen that thecounterbalance of my invention is mounted on the crank 2| and may beadjusted to give maximum counterbalancing action or partialcounterbalancing action, to move the center of mass either ahead or tothe rear of the center line A-A, or may be moved into a concentric, orneutral, or flywheel position so that the apparatus may be used foroperations other than pumping. It will further be seen that the movingof the counterweights 28 into any desired position is very readilyaccomplished by adjusting the nuts 44 to proper positions on the rods39, and that when the rods are secured in any given position a rigidattachment is provided. It will furthermore be seen that the weight ofthe counterbalance may be increased by use of the added weights 52 whichmay be of any desired weight, this being accomplished by the extent ofcoring, as indicated by dotted lines 53 in Fig. 4. A further importantfeature is the positioning of the added weights in sidewardly-facingpockets so that the force produced by rotation of the counterbalance istaken directly against the outer wall 50 of each pocket and is thereforetransmitted directly to the counterweight 28 and not through anyattaching means, the attaching means being employed solely for thepurpose of holding the weights from falling sidewardly from the pocketsI claim as my invention:

1. In a counterbalance construction, a rotatable shaft, a crank armsecured to said shaft, a pair of counterweights, means for pivotallymounting said counterweights one on each side of said crank arm foradjusting movements in the plane of rotation of the crank arm, and meansfor effecting independent adjusting movements of the counterweightsabout their pivots and for supporting said counterweights during andafter adjustment, said adjusting means comprising a rod for eachcounterweight pivotally connected to the same at a point spaced radiallyof its pivotal mounting and pivotally and adjustably connected to thecrank arm on the side of the shaft opposite the counterweight mountingmeans.

2. In a counterbalance construction, a rotatable shaft, a crank armsecured to said shaft, a pair of sector shaped counterweights, means forpivotally mounting said counterweights at their apexes one on each sideof said crank arm for adjusting movements in the plane of rotation ofsaid crank arm and with the pivots equispaced radially of the shaft, andmeans for effecting independent adjusting movements of thecounterweights about their pivots and for supporting said counterweightsduring and after adjustment, said adjusting means comprising a rod foreach counterweight pivotally connected to one edge portion of the sameat a point spaced radially of its pivotal mounting and pivotally andlongitudinally adjustably connected to the crank arm on the side of theshaft opposite the counterweight mounting means.

3. In a counterbalance construction, a rotatable shaft, a crank armsecured to said shaft, a pair of sector shaped counterweights, means forpivotally mounting said counterweights at their apexes one on each sideof said crank arm for adjusting movement in the plane of rotation ofSaid crank arm and with the pivots equi-spaced radially of the shaft,and means for effecting independent adjusting movements of thecounterweights about their pivots and for supporting said counterweightsduring and after adjustment, said adjusting means comprising a rod foreach counterweight pivotally connected to one edge portion of the sameat a point spaced radially of its pivotal mounting and pivotally andlongitudinally adjustably connected to the crank arm on the side of theshaft opposite the counterweight mounting means, each of saidcounterweights having a cut-away portion to provide clearance for therod of the other counterweight while said counterweights are in certainpositions of adjustment.

4. In a counterbalance construction, a rotatable shaft, a crank armsecured to said shaft,' a pair of counterweights, means for pivotallymounting said counterweights one on each side of said crank arm foradjusting movements in the plane of rotation of the crank arm, and meansfor effecting independent adjusting movements of the counterweightsabout their pivots and for supporting said counterweights during andafter adjustment, said adjusting means comprising a rod for eachcounterweight pivotally connected to the same at a point spaced radiallyof its pivotal mounting and pivotally and adjustably connected to thecrank arm on the side of the shaft opposite the counterweight mountingmeans, said rods lying in parallel planes to allow for crossing of thesame during certain positions of adjustment of the counterweights.

5. Ina counterbalance device of the character described, the combinationof: a crank arm adapted for use with a rotatable member; a pair ofcounterweights; pivot means connected to said crank arm intermediate theends thereof and supporting said counterweights one on each side of saidarm so as to swing into different counterbalancing positions relative tosaid arm; and means for effecting independent adjusting movement of saidcounterweights about said pivot means and for holding saidcounterweights during and after adjustment, said adjusting meanscomprising a rod for each counterweight, two pivotal connections foreach of said rods, one of said connections attaching said rod to acounterweight at a point spaced radially from said pivot means, and theother of said connections attaching said rod to said crank arm, one ofsaid connections having means for eifecting adjustment of the pivot axisof the connection along said rod to thereby change the effective lengthof said rod so as to swing the counterweight associated therewith onsaid pivot means.

6. In a counterbalance device of the character described, thecombination of t a crank arm adapted for use with a rotatable member; apair of counterweights; pivot means carried by said crank armintermediate the ends thereof and supporting said counterweights one oneach side of said arm so as to swing into different counterbalancingpositions relative to said arm; and means. for effecting independentadjusting movement of said counterweights about said pivot means and forholding said counterweights during and after adjustment of saidadjusting means, said adjusting means comprising a threaded rod for eachcounterweight, two pivotal connections for each of said rods, one ofsaid connections attaching said rod to a counterweight at a point spacedradially from said pivot means, and the other of said connectionsattaching said rod to said crank arm, one of said connections comprisinga head secured to the part to which it connects said rod, said headhaving a diametral opening through which said rod passes, and nuts onsaid rod on opposite sides of said head whereby rotation of said nuts onsaid rod will efiect adjustment between said head and said rod and swingsaid counterweight associated therewith on, said pivot means.

7. In a counterbalance device, the combination including: an. armadapted to be secured to a rotatable member; a pair of counterweights,one positioned on each side of said arm; means supporting saidcounterweights on said armv so that they are movable into diiferentcounterbalancing positions relative to the axis of rotation of said arm;and means for moving said counterweights into said differentcounterbalancing posito a rotatable member;

tions comprising a strut for each of said counterweights arranged at alltimes at an angle to the length of said arm and two pivotal connectionsfor each of said struts, one of said connections attaching said strut toa counterweight at a point removed from said counterweight supportingmeans, and the other of said connections attaching said strut to saidarm, and means for effecting adjustment oflthe pivot axis of one of saidconnections along said strut to thereby change the effective length ofsaid strut and move the counterweight associated therewith relative tosaid arm.

8. In a counterbalance device, the combination including: an arm adaptedto be secured a pair of counterweights, one positioned on each side ofsaid arm; means supporting said counterweights on said arm so that theyare movable into different counterbalancing positions relative to theaxis of rotation of said arm; and means for moving said counterweightsinto said different counterbalancing positions comprising a strut foreach of said counterweights arranged at all times at an angle to thelength of said arm and two pivotal connections for each of said struts,one of said connections attaching said strut to a counterweight at apoint removed from the counterweight supporting means, and the other ofsaid connections attaching said strut to said arm, and means operativelyassociated with said strut to vary the distance between the pivot axesof said pivotal connections to change the effective length of said strutand move the counterweight associated therewith relative to said arm.

WARREN M. MANSFIELD.

